Apparatus for fuel injection



Oct. 27, 1964 A. BLANCHARD 3,154,152

APPARATUS FOR FUEL INJECTION Filed July 10, 1962 2 Sheets-Sheet 1 FIG 1INVENTOR ANDREBLANCHARD 3M and ATTORNEY Oct. 27, 1964 A. BLANCHARD3,154,152

APPARATUS FOR FUEL INJECTION Filed July 10, 1962 2 Sheets-Sheet zATTORNEY United States Patent 3,154,152 APPARATUS FOR FUEL INJECTIONAndr Blanchard, 34 Rue Casteja, Bordeaux, Gironde, France Filed July 10,1962, Ser. No. 208,793 4 Claims. (Cl. 12332) The present inventionrelates to a method of supplying internal combustion engines with liquidfuel and also to devices for the practical application of this method.

The method essentially consists in introducing the liquid fuel in thechamber reserved for combustion (usually a cylinder) during the timealloted for the supply, under low pressure and through a plurality ofnozzles causing the fuel to flow into the combustion chamber laminarlyin a plurality of wiredrawn streams. Also, the method includessimultaneously subjecting said fuel in said combustion chamber to theaction of an electric field, either electrostatic or electromagnetic,the effect of this action being to cause said liquid to vaporize at ashort distance from the outlet of the liquid fuel into the combustionchamber.

It is recalled that a physical effect is employed at the outlet aspreviously claimed in the French Patent No. 1,117,341 filed by theapplicant on January 7, 1955, and the corresponding United States PatentNo. 2,826,513, Canadian Patent No. 699,287 and the British Patent No.793,958. The present application is a continuation-inpart of applicantsco-pending application Serial No. 818,387, filed June 5, 1959, andentitled Method and Devices for the Supply of Liquid Fuel to InternalCombustion Engines, now abandoned.

The device for the practical application of this method consistsessentially in at least one insulated conveyor nozzle which receives theliquid fuel under such a pressure that the flow of the liquid fuel atthe orifice outlets of the nozzle is Wiredrawn; in means for producingan electric field in the combustion chamber, these means beingcharacterized in that one electrode is placed in the interior of theinsulated nozzle into which the liquid fuel is conveyed, this electrodebeing separated from the orifice outlets of the nozzle by means of acolumn of liquid fuel, while the other electrode is the piston itself orthe combustion chamber itself which is grounded, the first of theseelectrodes being supplied with a high voltage current. Means areprovided to enable the flow of fuel through the nozzle to be regulatedin accordance with the heat of the engine in such manner as to producethe required number of fuel injections per unit of time.

Further features of the invention will become apparent from thedescription which follows below with reference to a number of forms ofembodiment, which are given by way of example and not in any sense byway of implied limitation.

FIG. 1 shows in diagrammatic form the supply elements of a cylinder;

FIG. 2 shows the injection device in greater detail;

FIG. 3 is a fragmentary, enlarged perspective of the control valve;

FIG. 4 is a detailed view, seen from the end, of an injection nozzlewith ten orifices;

FIG. 5 is a longitudinal axial cross-section of one of these orifices;

FIG. 6 is a diagram on a larger scale of the constantlevel supplychamber.

In FIG. 1, it may be seen that a source 1 is followed by an electronicsawtooth voltage generator 2 which increases the voltage and conveys itat a suitable frequency BJMJEZ Patented Oct. 27, 1964 to acontact-breaker 3 keyed on to the camshaft of the engine to be supplied.This contact-breaker distributes the voltage in appropriate sequence tothe various cylinders in such manner as to produce successive injectionsof liquid fuel into the cylinders, said fuel being conveyed from theconstant level tank through the piping systems 25. Contact-breaker 3 isillustrated as prepared for use with four cylinders. The ignitiondevice, which is not characterized by any special feature is illustratedin FIG. 1.

FIG. 1 shows the device which permits the creation of a pulsatoryvoltage of 10 kv. in an engine developing very high power with aconsumption of 36 liters per hour and a rotation speed of 6000 r.p.m.Since the injections take place at the rate of one for every tworevolutions there are therefore 3000 injections per minute. A verysimple calculation shows that each injection has a volume of 1.2 cu. mm.The pulsatory frequency to be adopted will therefore be substantiallyhigher than fifty pulses per second.

By way of example, the voltage of the source 1 (for example 12 v.) isobtained from a battery. This is rendered in sawtooth form by generator2, then applied to contactbreaker 3. The contact-breaker 3 is keyed onto the camshaft of the engine so as to cut off the high-voltage supplyat the bottom dead-center point of admission. In FIG. 1 piston 13 of thecylinder 4 is shown nearly in its top deadcenter position.

On the previous stroke, the exhaust valve 14 was opened under the actionof the camshaft 15 so as to allow the gases to escape, and thenreclosed: when the piston 13 begins to move down, the injectionoperation takes place (admission stroke). For this purpose, the inletvalve 16, which is controlled in the usual manner by the camshaft 17, isopened, thus putting the combustion chamber in communication with theopen air through the conduit 18' which supplies all the charging air.The combustion chamber is thus substantially at atmospheric pressure,less the reduction in pressure caused by the downward stroke of piston13.

injection of fuel through injection 26 takes place simultaneously withthe injection of air through valve 16. It is to be noted that at the endof the injection, at lowermost position of the piston 13 the airinlet-valve 16 will be closed and consequently tubes 13 and 18 which endon the upstream side of this valve will also be closed. However, duringthe injection stroke, the interior of the cylinder is put intocommunication with atmospheric pressure through the intermediary oftubes 18 and 18 thus tending to reduce to an appreciable degree thevacuum due to the downward stroke of the piston (which would be liableto modify the flow and therefore the force of the jet). Tube 18 providespressure equilibrium between tank 19 and the interior of the cylinderbefore closing of valve 16. Thus, tube 18 nullifies or cancels anydisturbances to which the nozzle is exposed in the combustion chamber.

The liquid fuel tank is located at 21. As in the case of normal types ofengines, the liquid fuel is sucked out by a pump 22 and is deliveredinto the auxiliary tank 23 which is movable vertically, and theoperation of which will be described below. This tank 23 is providedwith an overflow tube and is coupled to the constant level chamber 19 bymeans of a flexible sleeve 23 (see also FIG. 6).

A conduit 25 starts from the constant level chamber 19 and conveys thefuel to the injector which is given the general reference 26. Thehorizontal portion of this conduit which terminates as the injector willbe insulated over a fairly considerable length l (l) on the upstreamside of the injector 26. Indeed, as the liquid fed to the injector isbrought to about 10,000 volts, it is necessary to insulate the pipe 25conveying this liquid over a sufi'icient length l (l) in order that theliquid column of length l (I) be suflicient for providing an ohmicresistance which prevents too high a voltage drop at the endcorresponding to the spray orifices opening into the cylinders of theengine.

A description now follows below with reference to the injector 26 proper(FIG. 2).

The supply of fuel conveyed from the constant level chamber iscontrolled by the valve 26 which is inserted in the conduit 25. Thiscylindrical valve of insulating material is mounted so as to be capableof rotating in a nylon block 29 and is driven by the camshaft, asordinary inlet valve, the purpose being to open and close the inlet ductexactly at the required moment. It is provided with a recess 28 (FIG. 3)and is arranged to be displaceable vertically in addition to beingrotatable so as to open selectively recess 28. Thus, in the course ofthe inlet stroke, the rotational movement of valve 27 permits thearrival of the fuel through the conduit 25. The quantity of fuel soadmitted depends upon the axial position of valve 27, orifice 28 beingconfigured to permit the greatest quantity of fuel to be admitted whilevalve 27 is in its lowest position as indicated in FIG. 2.

The nylon block 29 is inserted on a block of quartz 31 which containsthe injection orifices and which is flared externally at the approach tothe cylinder so as to avoid any short-circuit between the outlets of theorifices and the metallic wall of the cylinder 4.

The high voltage supply, which is brought in through the connection 32and is derived from the contact-breaker 3, emerges in the insulatingportion of the tube 25 at A, at a distance from the injection nozzleswhich is suflicient to avoid the risk of incurring short-circuitsbetween the electrode constituted by this extremity of the connection 32and the other electrode formed by the cylinder 4.

The inlet conduit 25 does not open directly into the cylinder, but isflared out at 33 in such manner as to supply a series of nozzles whichare shown in end-view FIG. 4 and in longitudinal cross-section in FIG.5. Each nozzle comprises (FIG. a metallic tube 34 supported entirelywithin insulating material and terminating at the orifice proper 35(FIG. 4). It can be seen (FIG. 4) that the orifices are arranged in asymmetrical group with respect to the horizontal center line e-f. It hasbeen found that the diameter of tube 34 should be slightly larger ingasoline-powered than in kerosene-powered engines. Metallic tube 34carries the carburent which is at high potential and insulated from theground, since tube 34 is itself supported entirely within insulatingmaterial. Since tube 34 is itself non-insulative, it maintains the highpotential in the carburent. If tube 34 were insulating, there would notbe a sharp potential variation between the carburent and the chargingair.

The manner in which the engine can be made to accelerate by causing thelevel of liquid fuel to vary by means of the accelerator will now beexplained with reference to FIGS. 1 and 6. FIG. 1 shows a simple devicecontrolled by the accelerator and designed to vary the height of tank23. In the vicinity of the constant level chamber 19 and coupled tochamber 19 by means of a flexible tube 24, is located an auxiliary tank23 mounted in such manner as to rise or fall under the action of theaccelerator pedal, by means of a suitable mechanism. This auxiliary tank23 receives the fuel conveyed by pump 2 through pipe 41. This tank isfurthermore, rigidly fixed to an overflow pipe 42 which returns theexcess fuel to the main tank 21.

It can be seen in FIG. 6 that fuel passes into auxiliary tank 23 byfirst passing through a perforated surface 43, the holes of which are sodesigned as to avoid the effects of eddies and air bubbles in case ofexcessive movement of tank 21 which would otherwise create troublesomeair bubbles and undesirable effects on the flow of fuel.

The overflow tube 42 is provided at its upper portion with a check-valve45 controlled by a light spring. This check-valve closes as soon assuction takes place in the cylinders, in order that the vacuum shouldnot be transmitted to fuel tank 21.

The overall operation of the device is as follows:

As the flow of fuel reaches the cylinders of the engine, a sawtoothpulse of high voltage is applied so as to burst or vaporize the fuel.The flow of fuel is adjusted so as to issue from nozzles 35 laminarly orin wiredrawn streams. The voltage creates an intense electric fieldbetween the electrode 32 and the conductive grounded portions of thecylinders, and said voltage being applied at the correct instant, thefuel jets burst. This phenomenon which is now well known, has beendescribed in the applicants US. Patent No. 2,826,513.

The flow of fuel through valve 27 and then into the combustion chamberis synchronized with the application of the electric field within thechamber. This synchronization is possible because of the low pressureexisting in fuel line 25, on both sides of valve 27. This low pressureis permitted, since an electric field, instead of high pressure, is usedto vaporize the fuel. In conventional diesel fuel injection systems thehigh pressure used for vaporization results in a constant dribbling offuel into the chamber with attendant noxious and wasteful effects. Airis admitted through valve 16 which is sized to admit ten to twelve timesthe amount of air as fuel is admitted through valve 27. This air isinjected both prior to and during vaporization, cam 17 being designed toobtain this result.

I claim:

1. A device for feeding the combustion chamber of an internal combustionengine with fuel, comprising at least one electrically insulated nozzleopening into said combustion chamber, said nozzle including a pluralityof fuel introduction orifices communicant with said chamber and anoutwardly flared chamber within said nozzle and in front of saidorifices, means for supplying said nozzle with liquid fuel, and electricfield generating means for creating such an electric field within saidchamber as to cause vaporization of said fuel in the vicinity of saidnozzle, consisting of an electrode accommodated within the insulatednozzle and ending short of the outlet of said nozzle at a distancesufficient to avoid short circuit between said electrode and saidcombustion chamber and means for applying voltage to said electrode; andsaid combustion chamber including grounded portions.

2. Device as claimed in claim 1, wherein the said means for supplyingliquid fuel comprise a constant level fuel tank communicating with thenozzle, an auxiliary tank movable upwards and downwards relatively tothe constant-level tank, a flexible tube interconnecting said tanks, anaccelerator control member connected to said auxiliary tank foradjusting the position thereof, and a fuel pump discharging into saidauxiliary tank.

3. Device as claimed in claim 2, wherein the auxiliary tank comprises anoverflow pipe movable bodily with said auxiliary tank, and a check valvein said pipe for preventing back-flow suction therethrough.

4. A device for feeding the combustion chamber of an internal combustionengine with fuel comprising:

(A) at least one electrically insulated nozzle opening into saidcombustion chamber, said nozzle including a plurality of metal-linedfuel introduction orifices communicant with said chamber and anoutwardly flared chamber in front of said orifices,

(B) means for supplying said nozzle with liquid fuel including a rotaryvalve driven in rotation by the engine cam shaft so as to admit fuel inthe injection stroke of said combustion chamber, said valve beingfurther capable of displacement axially so as to increase or decreasethe amount of fuel injected,

5 6 (C) electric field generating means for creating such ReferencesCited by the Examiner an electric field within said chamber as to causeUNITED STATES PATENTS vaporization of said fuel in the vicinity of saidnozzle,

said electric field generating means consisting of an 20931339 9/37PiPPig 123-32 electrode accommodated Within the insulated nozzle 52,331,912 10/43 Holthouse 123 32 and ending short of said chamber andsaid orifices of 21436090 2/48 BQdmB 123 32 2,578,145 12/51 Miller123-32 said nozzle at a distance sufficient to avoid short circuitbetween said electrode and a grounded portion of said combustion chamberand means for applying voltage current to said electrode. 10

RICHARD B. WILKINSON, Primary Examiner.

1. A DEVICE FOR FEEDING THE COMBUSTION CHAMBER OF AN INTERNAL COMBUSTIONENGINE WITH FUEL, COMPRISING AT LEAST ONE ELECTRICALLY INSULATED NOZZLEOPENING INTO SAID COMBUSTION CHAMBER, SAID NOZZLE INCLUDING A PLURALITYOF FUEL INTRODUCTION ORIFICES COMMUNICANT WITH SAID CHAMBER AND ANOUTWARDLY FLARED CHAMBER WITHIN SAID NOZZLE AND IN FRONT OF SAIDORIFICES, MEANS FOR SUPPLYING SAID NOZZLE WITH LIQUID FUEL, AND ELECTRICFIELD GENERATING MEANS FOR CREATING SUCH AN ELECTRIC FIELD WITHIN SAIDCHAMBER AS TO CAUSE VAPORIZATION OF SAID FUEL IN THE VICINITY OF SAIDNOZZLE, CONSISTING OF AN ELECTRODE ACCOMMODATED WITHIN THE INSULATEDNOZZLE AND ENDING SHORT OF THE OUTLET OF SAID NOZZLE AT A DISTANCESUFFICIENT TO AVOID SHORT CIRCUIT BETWEEN SAID ELECTRODE AND SAIDCOMBUSTION CHAMBER AND MEANS FOR APPLYING VOLTAGE TO SAID ELECTRODE; ANDSAID COMBUSTION CHAMBER INCLUDING GROUNDED PORTIONS.